1. J.M. Gabrielse VEX Grippers (Devices that can attach to objects)

2. J.M. Gabrielse Outline Gripper Theory –Control –Speed Common Types of Grippers –Servo Grip –Motorized Grip –Pneumatic Grip –Roller Grip Challenge Hints –Use Lock Bars to attach devices to axles –Use an Ultrasonic Ranger to find objects Vex Labs Gridiron Robot

3. J.M. Gabrielse Control Holy grail of gripping: –Get object fast –Hang on –Let go quickly This must be done under excellent control –Limit switches –Auto-functions –Ease of operation

4. J.M. Gabrielse Speed Quickness covers mistakes –Quick to grab –Drop & re-grab Fast –Servo gripper –Pneumatic gripper Not fast –Roller gripper –Motor gripper

5. J.M. Gabrielse Servo Grip Precise Limited range of motion Limited torque Robert’s ARL robot in 2006

6. J.M. Gabrielse Motorized Grip Can be geared for speed or torque More complex FVC Team 31 in 2005

7. J.M. Gabrielse Some robot Pneumatic Grip Powerful Reliable Requires entire (unreliable) pneumatics system

8. J.M. Gabrielse Roller Grip Slow Allows for misalignment when grabbing Won’t let go Extends object as releasing Simple mechanism FVC Team 34 in 2005

9. J.M. Gabrielse Gripper Challenge

10. J.M. Gabrielse Lock-Bars Lock-bars allow for any component to be attached to an axle and rotated by a motor or servo. Axles fit through the square holes. Bolts fit through the round holes.

11. J.M. Gabrielse Ultrasonic Range Finder Detect the distance to the nearest object or wall –Bounces sound waves off of objects and measures the time it takes sound waves to return –The time can be used to calculate distances from 3 cm to 3 m

12. J.M. Gabrielse Thanks/Resources Designing Competitive Manipulators: The Mechanics & StrategyDesigning Competitive Manipulators: The Mechanics & Strategy by Greg Needel (www.robogreg.com)www.robogreg.com